 From VOA Learning English, this is the technology report in special English. Researchers are studying how mobile phones can help to document the spread of malaria. The study is part of an effort to stop or at least control the disease, which killed an estimated 655,000 people in 2010. Scientists say malaria-carrying mosquitoes cannot travel far on their own, but they can catch rides on people. That is what Harvard University researchers discovered in Kenya. They found that people carry the disease east from Lake Victoria to the capital, Nairobi. How did they discover this? The answer is simple. They followed their phones. Harvard Public Health researchers studied the mobile phone records of 15 million Kenyans who travel. Researchers estimated the distance and length of each phone user's trip away from home. This information was based on messages to and from the mobile phone carriers' 12,000 transmission towers. The researchers then compared that information to a map showing reports of malaria in different parts of the country. The researchers then estimated each user's probability of being infected in a given area. They also estimated the likelihood that a visitor to that area would become infected. The result was a picture showing malaria transmission paths starting in Lake Victoria. Carolyn Bucky is an assistant professor of epidemiology at Harvard. She says one of the first steps in stopping malaria is to learn how human travel might add to its spread. Carolyn Bucky also says researchers are considering using mobile phone records in other areas to help identify malaria transmission paths. For VOA Learning English, I'm Alex Villareal.